Hiroshi is ordered to collect the fruit of cactus and is transferred to Mexico. So, Nohara family is forced to move to Mexico and live there. They bid farewell to their acquaintances and the citizens of Kasukabe in tears. Shinchan heard that Mexican young girls are stylish and beautiful and became eager for this journey. On arriving at Madakueruyobaka city in Mexico, a new life full of anxiety, surrounded by unique neighbours awaits them. But Shinnosuke and Nohara family had no idea that flesh-eating killer cactuses are going to attack.
Now it is up to Nohara family along with the neighbours of Mexico to overcome this trouble.
In Mexico, in the town of Madakueruyobaka (fictional place), a new species of cactus was discovered. From the bud of the cactus, delicious and sweet honey could be made. Futaba Shouji, the company where Hiroshi worked, had put an eye on this. The company saw this as a business opportunity; it wanted to import and sell this commodity in Japan and outside. So, the company decided to open a branch office in Madakueruyobaka. Hiroshi was made the president of the Madaukeruyobaka branch, and was ordered transfer to Mexico.
Hiroshi had initially decided to go alone. But his wife Misae strongly opposed this. She argued that it would hamper the growth of their children, and said that a family is useless if it is not together. So it was decided that Hiroshi would move to Mexico with his family together.
At Futaba Kindergarten, Miss Yoshinaga announced that Shinnosuke would be leaving Kasukabe and moving to Mexico, which shocked everyone. All the Kasukabe Defense Group members expressed sorrow, except Kazama-kun who pretended that he’s not sad and remained calm. Ai-chan, who has a crush on Shin-chan, cried for him.
Shinchan realized that he would separated from Nanako. He said that, “I will remain in Kasukabe. I shall marry Nanako and live in Kasukabe”. But when Shinnosuke was told that Mexican girls are beautiful and glamorous, he decided to go.
Nohara family packed their belongings, and their house appeared empty. They felt sad and nostalgic for leaving their house full of memories. Their luggage was transported before their actual departure.
On the day of leaving, all the people of Kasukabe came together to bid farewell to the Nohara family. The Kasukabe Defense Group had come with a KB (Kasukabe Boueitai) badge, and gave it to Shinnkosuke. They said that, “Wherever in the world you go, if you have this badge, you shall remain a Kasukabe Boueitai member”. All members except Kazama-kun had arrived. Even the Saitama Red Scorpions, who considered Shin-chan a nuisance, had come. The Nohara family took a taxi to Kasukabe station. From the station, they boarded a train to the International Airport. When the train moved, in the middle of a dry river, Kazama was seen running behind. Shinnosuke and Kazama both called each other’s names, with tears, and Kazama still running behind the train. Finally they lifted their KB badge together and waved goodbye.
At the airport, Hiroshi was amazed at the speed of the airport crew. Huge aeroplanes could be seen landing and taking off. They boarded their flight to Mexico. They finally arrived at Mexico. They stayed at the seaside resort, and took a long-distance bus to Madakueruyobaka. On reaching, they saw that it is a small and remote town, cut-off from the big cities, and isolated. From there, they meet José, the only employee from the Futaba Shouji’s Mexico branch. José couldn’t speak Japanese, except for few words and phrases. From his dialogue “zenzen daijoubu” (totally fine), Hiroshi and others mistook that he is fluent in Japanese. He took them to their new house. In the pamphlet given by the company, the house looked gorgeous and nice. But when they reached there, they saw that the house was only halfway made with brick walls and windows, looking tattered. They had to accept it, looking at the body language of José.
Nohara family begin their new life in Mexico. They quickly adapted to the surroundings. They adjusted to Mexican food, which was very different from their own Japanese food. They learnt Spanish, so as to be understood by the locals. They even wore the traditional Mexico attire. Shinnosuke went to the local kindergarten. The teacher Carolina was a beauty having a nice body. Shinnosuke was delighted and fell in love with her.
On the way, Shin-chan encountered a girl who was always busy with her smartphone. When he spoke to her, she ignored him and said, “Don’t touch my phone, you potato-head”. Shinnosuke named her “Sumaho-chan”, though her real name was Fransisca. The family also encountered two interesting locals. One was Nene Rodriguez, a masked professional Luchador wrestler. The other person was Mariachi, a man who loved singing and always played the guitar.
This town, in the old days, was poor in industry and many people had left in search of work. But thanks to the cactus, the town seemed to escape from crisis. The Mayor wanted to further develop the town and attempted to harvest and sell only to the locals. When Hiroshi met the Mayor to negotiate, he refused. He said that many outsiders are attracted to the sweet nectar of the cactus. He refused to sell the cactuses or permit business. Meanwhile, in the square with the new cactus, a cactus festival was held. Shinnosuke wanted to dance with the kindergarten teacher Carolina, so he insisted Hiroshi to take him to the festival. Everyone in the festival was having a nice time.
There was a huge cactus which was about to bloom. The people including the Mayor were waiting for it to flower. But immediately after blooming, it turns into a giant killer cactus. From this giant Queen Cactus, small killer cactuses were generated. They started swallowing the people one after the other. All the terrified people started running, with the cactuses chasing them and eating them up. The town was getting destroyed. The cactus researcher, Ikegamino, said that cactuses have a strong regenerative power and it would be difficult to destroy them.
Nohara family including some residents, fled to one of the nearby bars. Hiroshi suggested that they should run out of the town, but no one cooperated fearing that they would be attacked by cactuses. At the bar they drank cola; there was no milk for Himawari. So Hiroshi decided to get some from the closest supermarket. Sumaho-chan accompanied him, in order to get a charger for her smartphone. But when they returned, the killer cactus also reached the bar and started eating people. So they had to escape again. Meanwhile, their dog Shiro was left behind in their house in the town. Shiro bravely saved some stray dogs from the cactus attack.
Hiroshi bought a bus from the bus stop and the residents boarded it. But they got eaten up even on the way. The person who were alive were the Nohara family, the Mayor, Carolina, Fransisca, Nene Rodriguez, Mariachi and the Nihon Erekiteru Union. The Nihon Erekiteru Union is a comedy group of Japan, consisting of Hosogai-san and Akemi-chan. Hosogai-san was an officer and Akemi-chan was Chibikko. On the bus, they both got soon eaten up by cactuses. Chibikko said her famous lines “Dame yo, Dame Dame” (No, no), before getting eaten. The rest fought with the cactus. The bridge which lead out of the town was occupied by killer cactuses, so they had to turn back. Shinnosuke discovered that cactuses hit people by responding to sound. But soon the bus driver got eaten up and the bus crashed onto a mountain.
At the suggestion of the Mayor, the survivors escaped into the Cactus amusement park nearby. The park was still under construction. There was no food available. So they decided that they had no choice but to leave the town. But the Mayor was strongly opposed to this. They discovered dynamite in the prefabricated hut for construction workers. They made a plan to blow up the cactus in the town. The Mayor was again opposed to blow up cactus in the town. So they decided to blow the cactus outside the town. They tied dynamite to a vehicle called “Cactus Car”, and from the nature of cactuses reacting to sound, the strategy was to take the cactus out of the town and blow them across the bridge. When the cactus followed the vehicle, a fruit of the cactus fell down. The tempted Mayor went to pick up the fruit but fell down and by mistake changed the direction of the vehicle. As a result, the vehicle blew up on the bridge itself. Thus, the only exit of the city was collapsed.
The cactus started attacking again. In order to escape, Hiroshi and Misae wandered. Shinnosuke and Mayor were left together. They planned to go back to the town to get food. The Mayor talks about the reconstruction of the town to Shinnosuke. According to him, Madakueruyobaka was a poor countryside town and he grew up in this town. Now since many people have left, the town is deserted like nothing. So he intends to use this new cactus species to revitalize the town.
Shinnosuke ate the food that was passed from the Mayor and wanted to have a pee. But it was forbidden by Mayor’s law to stand and pee on the roads. So, he had to go into the fields to pee. While peeing, a small killer cactus came near him. Shinnosuke peed on the cactus. To his surprise, the cactus got wrinkled and died. He wondered if pee was the weakness of the cactus. He told this thing to the Mayor, who was still busy thinking of his revitalization plan. Then they all realized that the weakness of cactus is water.
They decided to defeat the killer cactus using water. But there was shortage of water in the city. At the suggestion of Carolina and Francisca, they decided to use the water of the water supply tank on Chichideka mountain. The Mayor was again opposed to use the water from the tank, but had to give up this time. He let out his anger on Sumaho-chan. Hiroshi’s plan was to inject water into a playing balloon called “Sabo-chan”, and throw it at the Queen Cactus.
The action started with the day after sunrise. The “Madakueruyobaka Defense Group” was formed. The Queen Cactus had grown into a huge monster. They were likely to be attacked during water injection, so someone had to play the role of decoy. Mariachi was chosen as the decoy and he asked help from Rainbow Kamen in fear. In their dedication, water was able to get filled in the Sabo-chan balloon. But suddenly the Queen Cactus which was stationary began to move, and attacked Mariachi and Rainbow Kamen. The Mayor could see his town getting destroyed. In order to help Mariachi and Rainbow Kamen, the hitherto uncooperative Mayor himself became the decoy. While he was busy distracting the cactus, Hiroshi rolled the water-filled Sabo-chan balloon down the mountain and it was thrown at the Queen Cactus. The balloon was supposed to be burst by the thorns of the cactus and water was supposed to spout. But, the Queen Cactus guarded the balloon with its tentacles which had no thorn and it didn’t burst.
So, Shinnosuke took out the needle of the KB badge which he was wearing. Kazama-kun had made the needle as a safety pin of the KB badge. Shinnosuke had almost forgotten about its existence; and it proved to be very helpful at the right time. Then Shinnosuke ran with the needle in hand, jumped and pierced the balloon with it. The balloon got burst, with water spouting all over. The Queen cactus got exhausted, was defeated and got disappeared. Also, all people which it had swallowed were alive and came out. The botanist Ikegamino gave the reason that carnivorous plants take time to digest the things they eat.
Peace returned to town and the Cactus Festival resumed. Shinnosuke was able to dance with Carolina which he had been waiting since long. The species of new cactus was never seen again. So, the Mexico branch of Futaba Shouji was shut down, and Hiroshi was recalled back to the headquarters in Japan. Everyone happily enjoyed at the Cactus Land amusement park. Meanwhile, in Japan, Kazama received an international mail from Shinnosuke. There he had stated that since the new cactus doesn’t exist anymore, they would be returning home soon. Kazama was overjoyed on reading this.
Finally the Nohara family returned to Kasukabe after their adventure in Mexico.